The union picketed the Constitution Place construction site in May 2018, accusing Dale and Hitchcock Civil Engineering and Landscaping of not paying workers wages and allowances in line with the award. The company strongly denied the claims.

Now the commission has accused the union of orchestrating the picket in order to force the company to make an enterprise agreement with the union, breaking federal building and fair work laws in the process.

It has alleged up to 20 picketers placed chains on gates at the construction site, and glued locks to the main truck access gate.

The commission has also alleged picketers pushed and shoved workers who were trying to enter the site during the two-and-a-half hour picket. A CFMEU official is alleged to have told a group of workers: "you'll have to go through me to get in".

CFMEU ACT secretary Jason O'Mara, assistant branch secretary Zach Smith, and organisers Kenneth Miller, Lorenzo White and Josh Bolitho have all been named in the action.

In a statement, Mr O'Mara said the commission filed six matters nationally over the last two weeks "to assist the Liberal party in the upcoming election".

"We regard this matter and other matters being brought by the ABCC as being without merit and they will be vigorously defended," he said.

Federal Labor has promised to abolish the construction watchdog if it wins government.

Master Builders Association ACT chief executive Michael Hopkins said the court action "proves why the Australian Building and Construction Commission must be retained".

The site is being developed by the Snow family's Capital Property Group, who won an ACT government tender to redevelop the 9000 square metre car park in 2016 into two buildings.

One building will be leased by the government for at least 20 years and house 1700 ACT public servants.

The other building will provide 12 levels of commercial offices and a five-star Adina Apartment Hotel Grand with 132 rooms over four levels.